text: #!/usr/bin/env python2
  # Copyright (c) 2014-2015 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #
  # Test pruning code
  # ********
  # WARNING:
  # This test uses 4GB of disk space.
  # This test takes 30 mins or more (up to 2 hours)
  # ********
  
  from test_framework.test_framework import UtabitTestFramework
  from test_framework.util import *
  
  def calc_usage(blockdir):
      return sum(os.path.getsize(blockdir+f) for f in os.listdir(blockdir) if os.path.isfile(blockdir+f))/(1024*1024)
  
  class PruneTest(UtabitTestFramework):
  
      def __init__(self):
          self.utxo = []
          self.address = ["",""]
          self.txouts = gen_return_txouts()
  
      def setup_chain(self):
          print("Initializing test directory "+self.options.tmpdir)
          initialize_chain_clean(self.options.tmpdir, 3)
  
      def setup_network(self):
          self.nodes = []
          self.is_network_split = False
  
          # Create nodes 0 and 1 to mine
          self.nodes.append(start_node(0, self.options.tmpdir, ["-debug","-maxreceivebuffer=20000","-blockmaxsize=999000", "-checkblocks=5"], timewait=900))
          self.nodes.append(start_node(1, self.options.tmpdir, ["-debug","-maxreceivebuffer=20000","-blockmaxsize=999000", "-checkblocks=5"], timewait=900))
  
          # Create node 2 to test pruning
          self.nodes.append(start_node(2, self.options.tmpdir, ["-debug","-maxreceivebuffer=20000","-prune=550"], timewait=900))
          self.prunedir = self.options.tmpdir+"/node2/regtest/blocks/"
  
          self.address[0] = self.nodes[0].getnewaddress()
          self.address[1] = self.nodes[1].getnewaddress()
  
          # Determine default relay fee
          self.relayfee = self.nodes[0].getnetworkinfo()["relayfee"]
  
          connect_nodes(self.nodes[0], 1)
          connect_nodes(self.nodes[1], 2)
          connect_nodes(self.nodes[2], 0)
          sync_blocks(self.nodes[0:3])
  
      def create_big_chain(self):
          # Start by creating some coinbases we can spend later
          self.nodes[1].generate(200)
          sync_blocks(self.nodes[0:2])
          self.nodes[0].generate(150)
          # Then mine enough full blocks to create more than 550MB of data
          for i in xrange(645):
              self.mine_full_block(self.nodes[0], self.address[0])
  
          sync_blocks(self.nodes[0:3])
  
      def test_height_min(self):
          if not os.path.isfile(self.prunedir+"blk00000.dat"):
              raise AssertionError("blk00000.dat is missing, pruning too early")
          print "Success"
          print "Though we're already using more than 550MB, current usage:", calc_usage(self.prunedir)
          print "Mining 25 more blocks should cause the first block file to be pruned"
          # Pruning doesn't run until we're allocating another chunk, 20 full blocks past the height cutoff will ensure this
          for i in xrange(25):
              self.mine_full_block(self.nodes[0],self.address[0])
  
          waitstart = time.time()
          while os.path.isfile(self.prunedir+"blk00000.dat"):
              time.sleep(0.1)
              if time.time() - waitstart > 10:
                  raise AssertionError("blk00000.dat not pruned when it should be")
  
          print "Success"
          usage = calc_usage(self.prunedir)
          print "Usage should be below target:", usage
          if (usage > 550):
              raise AssertionError("Pruning target not being met")
  
      def create_chain_with_staleblocks(self):
          # Create stale blocks in manageable sized chunks
          print "Mine 24 (stale) blocks on Node 1, followed by 25 (main chain) block reorg from Node 0, for 12 rounds"
  
          for j in xrange(12):
              # Disconnect node 0 so it can mine a longer reorg chain without knowing about node 1's soon-to-be-stale chain
              # Node 2 stays connected, so it hears about the stale blocks and then reorg's when node0 reconnects
              # Stopping node 0 also clears its mempool, so it doesn't have node1's transactions to accidentally mine
              stop_node(self.nodes[0],0)
              self.nodes[0]=start_node(0, self.options.tmpdir, ["-debug","-maxreceivebuffer=20000","-blockmaxsize=999000", "-checkblocks=5"], timewait=900)
              # Mine 24 blocks in node 1
              self.utxo = self.nodes[1].listunspent()
              for i in xrange(24):
                  if j == 0:
                      self.mine_full_block(self.nodes[1],self.address[1])
                  else:
                      self.nodes[1].generate(1) #tx's already in mempool from previous disconnects
  
              # Reorg back with 25 block chain from node 0
              self.utxo = self.nodes[0].listunspent()
              for i in xrange(25): 
                  self.mine_full_block(self.nodes[0],self.address[0])
  
              # Create connections in the order so both nodes can see the reorg at the same time
              connect_nodes(self.nodes[1], 0)
              connect_nodes(self.nodes[2], 0)
              sync_blocks(self.nodes[0:3])
  
          print "Usage can be over target because of high stale rate:", calc_usage(self.prunedir)
  
      def reorg_test(self):
          # Node 1 will mine a 300 block chain starting 287 blocks back from Node 0 and Node 2's tip
          # This will cause Node 2 to do a reorg requiring 288 blocks of undo data to the reorg_test chain
          # Reboot node 1 to clear its mempool (hopefully make the invalidate faster)
          # Lower the block max size so we don't keep mining all our big mempool transactions (from disconnected blocks)
          stop_node(self.nodes[1],1)
          self.nodes[1]=start_node(1, self.options.tmpdir, ["-debug","-maxreceivebuffer=20000","-blockmaxsize=5000", "-checkblocks=5", "-disablesafemode"], timewait=900)
  
          height = self.nodes[1].getblockcount()
          print "Current block height:", height
  
          invalidheight = height-287
          badhash = self.nodes[1].getblockhash(invalidheight)
          print "Invalidating block at height:",invalidheight,badhash
          self.nodes[1].invalidateblock(badhash)
  
          # We've now switched to our previously mined-24 block fork on node 1, but thats not what we want
          # So invalidate that fork as well, until we're on the same chain as node 0/2 (but at an ancestor 288 blocks ago)
          mainchainhash = self.nodes[0].getblockhash(invalidheight - 1)
          curhash = self.nodes[1].getblockhash(invalidheight - 1)
          while curhash != mainchainhash:
              self.nodes[1].invalidateblock(curhash)
              curhash = self.nodes[1].getblockhash(invalidheight - 1)
  
          assert(self.nodes[1].getblockcount() == invalidheight - 1)
          print "New best height", self.nodes[1].getblockcount()
  
          # Reboot node1 to clear those giant tx's from mempool
          stop_node(self.nodes[1],1)
          self.nodes[1]=start_node(1, self.options.tmpdir, ["-debug","-maxreceivebuffer=20000","-blockmaxsize=5000", "-checkblocks=5", "-disablesafemode"], timewait=900)
  
          print "Generating new longer chain of 300 more blocks"
          self.nodes[1].generate(300)
  
          print "Reconnect nodes"
          connect_nodes(self.nodes[0], 1)
          connect_nodes(self.nodes[2], 1)
          sync_blocks(self.nodes[0:3])
  
          print "Verify height on node 2:",self.nodes[2].getblockcount()
          print "Usage possibly still high bc of stale blocks in block files:", calc_usage(self.prunedir)
  
          print "Mine 220 more blocks so we have requisite history (some blocks will be big and cause pruning of previous chain)"
          self.nodes[0].generate(220) #node 0 has many large tx's in its mempool from the disconnects
          sync_blocks(self.nodes[0:3])
  
          usage = calc_usage(self.prunedir)
          print "Usage should be below target:", usage
          if (usage > 550):
              raise AssertionError("Pruning target not being met")
  
          return invalidheight,badhash
  
      def reorg_back(self):
          # Verify that a block on the old main chain fork has been pruned away
          try:
              self.nodes[2].getblock(self.forkhash)
              raise AssertionError("Old block wasn't pruned so can't test redownload")
          except JSONRPCException as e:
              print "Will need to redownload block",self.forkheight
  
          # Verify that we have enough history to reorg back to the fork point
          # Although this is more than 288 blocks, because this chain was written more recently
          # and only its other 299 small and 220 large block are in the block files after it,
          # its expected to still be retained
          self.nodes[2].getblock(self.nodes[2].getblockhash(self.forkheight))
  
          first_reorg_height = self.nodes[2].getblockcount()
          curchainhash = self.nodes[2].getblockhash(self.mainchainheight)
          self.nodes[2].invalidateblock(curchainhash)
          goalbestheight = self.mainchainheight
          goalbesthash = self.mainchainhash2
  
          # As of 0.10 the current block download logic is not able to reorg to the original chain created in
          # create_chain_with_stale_blocks because it doesn't know of any peer thats on that chain from which to
          # redownload its missing blocks.
          # Invalidate the reorg_test chain in node 0 as well, it can successfully switch to the original chain
          # because it has all the block data.
          # However it must mine enough blocks to have a more work chain than the reorg_test chain in order
          # to trigger node 2's block download logic.
          # At this point node 2 is within 288 blocks of the fork point so it will preserve its ability to reorg
          if self.nodes[2].getblockcount() < self.mainchainheight:
              blocks_to_mine = first_reorg_height + 1 - self.mainchainheight
              print "Rewind node 0 to prev main chain to mine longer chain to trigger redownload. Blocks needed:", blocks_to_mine
              self.nodes[0].invalidateblock(curchainhash)
              assert(self.nodes[0].getblockcount() == self.mainchainheight)
              assert(self.nodes[0].getbestblockhash() == self.mainchainhash2)
              goalbesthash = self.nodes[0].generate(blocks_to_mine)[-1]
              goalbestheight = first_reorg_height + 1
  
          print "Verify node 2 reorged back to the main chain, some blocks of which it had to redownload"
          waitstart = time.time()
          while self.nodes[2].getblockcount() < goalbestheight:
              time.sleep(0.1)
              if time.time() - waitstart > 900:
                  raise AssertionError("Node 2 didn't reorg to proper height")
          assert(self.nodes[2].getbestblockhash() == goalbesthash)
          # Verify we can now have the data for a block previously pruned
          assert(self.nodes[2].getblock(self.forkhash)["height"] == self.forkheight)
  
      def mine_full_block(self, node, address):
          # Want to create a full block
          # We'll generate a 66k transaction below, and 14 of them is close to the 1MB block limit
          for j in xrange(14):
              if len(self.utxo) < 14:
                  self.utxo = node.listunspent()
              inputs=[]
              outputs = {}
              t = self.utxo.pop()
              inputs.append({ "txid" : t["txid"], "vout" : t["vout"]})
              remchange = t["amount"] - 100*self.relayfee # Fee must be above min relay rate for 66kb tx
              outputs[address]=remchange
              # Create a basic transaction that will send change back to ourself after account for a fee
              # And then insert the 128 generated transaction outs in the middle rawtx[92] is where the #
              # of txouts is stored and is the only thing we overwrite from the original transaction
              rawtx = node.createrawtransaction(inputs, outputs)
              newtx = rawtx[0:92]
              newtx = newtx + self.txouts
              newtx = newtx + rawtx[94:]
              # Appears to be ever so slightly faster to sign with SIGHASH_NONE
              signresult = node.signrawtransaction(newtx,None,None,"NONE")
              txid = node.sendrawtransaction(signresult["hex"], True)
          # Mine a full sized block which will be these transactions we just created
          node.generate(1)
  
  
      def run_test(self):
          print "Warning! This test requires 4GB of disk space and takes over 30 mins (up to 2 hours)"
          print "Mining a big blockchain of 995 blocks"
          self.create_big_chain()
          # Chain diagram key:
          # *   blocks on main chain
          # +,&,$,@ blocks on other forks
          # X   invalidated block
          # N1  Node 1
          #
          # Start by mining a simple chain that all nodes have
          # N0=N1=N2 **...*(995)
  
          print "Check that we haven't started pruning yet because we're below PruneAfterHeight"
          self.test_height_min()
          # Extend this chain past the PruneAfterHeight
          # N0=N1=N2 **...*(1020)
  
          print "Check that we'll exceed disk space target if we have a very high stale block rate"
          self.create_chain_with_staleblocks()
          # Disconnect N0
          # And mine a 24 block chain on N1 and a separate 25 block chain on N0
          # N1=N2 **...*+...+(1044)
          # N0    **...**...**(1045)
          #
          # reconnect nodes causing reorg on N1 and N2
          # N1=N2 **...*(1020) *...**(1045)
          #                   \
          #                    +...+(1044)
          #
          # repeat this process until you have 12 stale forks hanging off the
          # main chain on N1 and N2
          # N0    *************************...***************************(1320)
          #
          # N1=N2 **...*(1020) *...**(1045) *..         ..**(1295) *...**(1320)
          #                   \            \                      \
          #                    +...+(1044)  &..                    $...$(1319)
  
          # Save some current chain state for later use
          self.mainchainheight = self.nodes[2].getblockcount()   #1320
          self.mainchainhash2 = self.nodes[2].getblockhash(self.mainchainheight)
  
          print "Check that we can survive a 288 block reorg still"
          (self.forkheight,self.forkhash) = self.reorg_test() #(1033, )
          # Now create a 288 block reorg by mining a longer chain on N1
          # First disconnect N1
          # Then invalidate 1033 on main chain and 1032 on fork so height is 1032 on main chain
          # N1   **...*(1020) **...**(1032)X..
          #                  \
          #                   ++...+(1031)X..
          #
          # Now mine 300 more blocks on N1
          # N1    **...*(1020) **...**(1032) @@...@(1332)
          #                 \               \
          #                  \               X...
          #                   \                 \
          #                    ++...+(1031)X..   ..
          #
          # Reconnect nodes and mine 220 more blocks on N1
          # N1    **...*(1020) **...**(1032) @@...@@@(1552)
          #                 \               \
          #                  \               X...
          #                   \                 \
          #                    ++...+(1031)X..   ..
          #
          # N2    **...*(1020) **...**(1032) @@...@@@(1552)
          #                 \               \
          #                  \               *...**(1320)
          #                   \                 \
          #                    ++...++(1044)     ..
          #
          # N0    ********************(1032) @@...@@@(1552) 
          #                                 \
          #                                  *...**(1320)
  
          print "Test that we can rerequest a block we previously pruned if needed for a reorg"
          self.reorg_back()
          # Verify that N2 still has block 1033 on current chain (@), but not on main chain (*)
          # Invalidate 1033 on current chain (@) on N2 and we should be able to reorg to
          # original main chain (*), but will require redownload of some blocks
          # In order to have a peer we think we can download from, must also perform this invalidation
          # on N0 and mine a new longest chain to trigger.
          # Final result:
          # N0    ********************(1032) **...****(1553)
          #                                 \
          #                                  X@...@@@(1552)
          #
          # N2    **...*(1020) **...**(1032) **...****(1553)
          #                 \               \
          #                  \               X@...@@@(1552)
          #                   \
          #                    +..
          #
          # N1 doesn't change because 1033 on main chain (*) is invalid
  
          print "Done"
  
  if __name__ == '__main__':
      PruneTest().main()
  